This invention generally relates to a screw body jack and a body jack assembly and in particular to a screw body jack and a body jack assembly for correcting the deformation of a car body or for deforming a metallic structure in general.
It is generally known to use a hydraulic jack for correcting the deformation of a car body which commonly arises from a car accident. And a variety of such body jacks and body jack kits are commercially available. But such hydraulic jacks are known to have various shortcomings.
First when correcting a local deformation of an integral body member such as a rear panel of a passenger car it is necessary to fix the body member to a post secured to the floor or a bench to support the reaction force arising as the cylinder of the body jack applies force to the body member. As a result, considerable time must be spent for preparatory work and additional space becomes necessary.
Second such a hydraulic jack is generally capable of producing force only in one direction at a time and, when correcting the deformation of an opening in one direction, a new deformation is often caused in other directions and corrections must be repeated over and over again before overall correction of the initial deformation is attained.
Third a hydraulic cylinder is generally so heavy that the user thereof gets tired very quickly from using it. And while a hydraulic jack can produce a large stroke very easily it can not produce small stroke with any accuracy, making it unsuitable for use in correcting small deformations.